This invention relates to a manually releasable fastener which may be substituted for conventional bolt and nut fasteners that are used for securing together the adjacent ends of conventional segment type pipe couplings.
One conventional type of pipe coupling comprises two or more curved segments which are assembled together, end-to-end, to encircle and couple the adjacent ends of a pair of axially aligned pipes. Typically, such couplings are provided with integral, radially outwardly extending lugs on the ends of the curved segments. These lugs are provided with bolt holes through which bolts are extended and fastened by nuts for securing the segments together to form the circular or ring-like coupling. In such couplings, both ends of each segment are formed with bolt receiving lugs. Adjacent lugs are secured together with conventional bolts and nuts. Alternatively, some of such couplings have segments which are provided with hinge components for hingedly connecting one segment to the adjacent end of the opposite segment. Then bolts and nuts are used to fasten the adjacent lugs that are formed on the opposite ends of segments. Examples of such couplings are described and illustrated in U.S. Pat. No. 4,915,418 issued to Josef Palatchy on Apr. 10, 1990 for a "Hinged Pipe Coupling," and in U.S. Pat. No. 4,966,395 issued to Thomas R. Hendrickson on Oct. 30, 1990 for a "Rigid or Flexible Coupling for Pipes," and in U.S. Pat. No. 5,018,768 issued to Josef Palatchy on May 28, 1992 for a "Pipe Coupling Hinge."
In such pipe couplings the curved segments are generally U-shaped in cross-section to provide side walls or legs that extend radially inwardly from a base. The inner free edges of the legs form keys or tenons which fit into circumferential grooves that are cut in the pipes, near the ends of the pipes. A rubber-like gasket is arranged within the space or channel formed by the U-shaped cross-section coupling segments. The gasket encircles and seals the adjacent ends of the pipes when the keys are placed within the pipe grooves.
Such couplings are typically used for water lines or for pipe lines for conducting other fluids or gases. By way of example, water lines may be formed of a large number of pipes that are coupled end-to-end. Each pipe is provided with circumferential grooves located near its opposite ends and the pairs of adjacent pipe ends are arranged close to each other. The coupling is then positioned around a pair of adjacent pipe ends and is secured in place to form a coupled joint.
Whether the segments are fastened together at one end by a hinge arrangement and at the opposite end by bolt-and-nut fasteners or, whether the segments are fastened together entirely by bolt-and-nut fasteners, the segments must be manually positioned around the pipe ends. Then considerable time is involved in manipulating and fastening the one or two bolt-and-nut fasteners. Although the time is minimal to fasten a single bolt-and-nut fastener, where numerous couplings are used, as for example, in a water line in a building, the aggregate time expended by the plumbing installer to fasten the bolts-and-nuts becomes considerable. Hence, it is desirable to have a coupling system in which the segments of the couplings can be manually assembled rapidly, without the need for wrenches or other tools. To meet that need, prior, commercially available, couplings have been made with toggle or lever types of fasteners for interlocking adjacent ends of coupling segments. Examples of such devices are shown in U.S. Pat. No. 4,123,095 issued to Theodore A. Stehlin on Oct. 31, 1978 for a "Pipe Clamp Having An Overcenter Toggle," and in U.S. Pat. No. 4,561,678 issued to Donald R. Kunsman on Dec. 31, 1985 for a "Pipe Coupling," and in Swiss Patent No. 390,637 granted to Societe de Constructions d'Appareils Mecaniques Inoxydables on Apr. 15, 1965.
Segmented pipe couplings that use bolt fasteners are relatively inexpensive to manufacture. In contrast, pipe couplings that use toggle fasteners, particularly where made with sufficient strength and rigidity for coupling relatively large pipes, are considerably more expensive to produce. Thus, it would be desirable to have available, for example, on a plumbing contracting job site, relatively inexpensive bolt-type fastened couplings with toggle-type fasteners, but without the additional expense of a conventional toggle-type coupling.
The invention herein relates to a fastener, similar to a toggle-type locking fastener, which may be manufactured and stored as an independent unit, and which may be substituted, whenever desired, for the typical bolt-and-nut fastener that is used in a conventional bolt-type coupling, so as to provide the low cost benefit of a bolt-type coupling with the high speed, manual assembly ability of a toggle-type coupling.